Four studies examined factors mediating the so-called "Barnum effect"-the acceptance of character descriptions composed of high base-rate personality traits as uniquely applicable to the self. Departing from previous research, all experiments examined the effect in a context in which subjects were not deceived into believing that the descriptions had been based on personal information supplied by them. In Study 1 subjects who rated the applicability of personality characteristics to themselves

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... iewed the characteristics as significantly more applicable than subjects asked to assess their applicability to an acquaintance. In Study 2 subjects estimated that they displayed both positive behaviors and their negatively valenced opposites more frequently than an acquaintance displayed them, indicating that the Barnum effect might be mediated by the greater availability of evidence to confirm traits in the self. In Studies 3 and 4 the perceived accuracy of paragraph-long personality descriptions increased with subjects' familiarity with the applicable individuals. Subjects rated the descriptions as most accurate for themselves, next most accurate for a close friend, next most accurate for a moderate friend, and least accurate for a casual acquaintance. In both of the latter studies, however, the influence of familiarity on perceived accuracy was largely confined to positively valenced descriptions. It was concluded that, in addition to being influenced by a prior belief in the credibility of a source, the Barnum effect may be mediated by a combination of cognitive and motivational factors.